The invention concerns urea being condensated with itself to produce cyanuric acid and cyamelide. The invention also concerns their preparation and use. These condensation compounds are useful to produce flame retardant plastics, to flame retard natural products, and may be reacted with phosphorus and/or boron containing compounds to produce other flame retardant compounds. These condensation compounds may also be reacted with aldehydes to produce cyanuric acid and cyamelide resins for use as molding compounds, as an adhesive, coating resin or as a flame retardant compound.
The heating of urea to produce urea condensation compounds, such as biuret and a mixture of cyanuric acid and cyamelide, is known in the arts, but the further condensation of flame retardant urea and buiret to produce a mixture of cyanuric acid and cyamelide which are improved flame retardant compounds is novel. The condensation of isocyanuric acid and/or cyanic acid, (which are produced by heating urea), produces the flame retardant, cyanuric acid and cyamelide compounds, is novel. The mixture of cyanuric acid and cyamelide compounds and their phosphorus and/or boron salts may be used as flame retardant compounds in plastics and natural products. Urea and melamine were utilized as a flame retardant compound by Fracalossi, et al., in U.S. Pat. No. 4,385,131. Melamine was utilized as flame retardant compounds in polyurethanes by Yukuta, et al., in U.S. Pat. No. 4,221,875 and by Grinbergs et al., in U.S. Pat. No. 4,745,133. Amino phosphates was utilized by Blount in U.S. Pat. No. 5,010,113.
What is lacking and what is needed are useful, safe and inexpensive flame retardant compound mixture of cyanuric acid and cyamelide. The urea condensation compounds, cyanuric acid and cyamelide, and their aldehyde resins are novel flame retardant compounds. What is additionally lacking are compositions having the urea condensation compounds, cyanuric acid and cyamelide, and/or their salts employed therein.
In one aspect, the invention comprises of the flame retardant mixture of cyanuric acid and cyamelide. Another aspect of the invention is a process to prepare a, mixture of cyanuric acid and cyamilide by heating and reacting:
(A) urea with itself or biuret;
under conditions sufficient to prepare the urea condensation mixture of cyanuric acid and cyamelide. The urea is first heated to produce isocyanuric acid and/or cyanic acid then reacted with urea to form biuret then further heated to form a mixture of cyanuric acid and cymelide.
In another aspect, the invention comprises cyanuric acid and cyamelide salts of phosphorus and/or boron containing compound and a process to prepare cyanuric acid and cyamelide salts of a phosphorus and/or boron containing compound employing phosphorus and/or boron containing compound that will react with the mixture of cyanuric acid and cyamelide under conditions sufficient to prepare the cyanuric acid and cyamelide salt of a phosphorus and/or boron containing compound, comprising serially contacting, heating and reacting:
(A) urea with itself;
(B) phosphorus and/or boron containing compound that will react with an amino condensation compound;
component A is first heated with itself or with biuret sufficient to produce cyanuric acid and cyamelide then component B is added and reacted.
An addition aspect of this invention is the production of a mixture of cyanuric acid-aldehyde and cyamelide-aldehyde resins, and a process to prepare a mixture of cyanuric acid and cyamelide-aldehyde resins under conditions sufficient to prepare the mixture of cyanuric acid-aldehyde and cyamelide-aldehyde resins comprising serially contacting, heating and reacting:
(A) a mixture of cyanuric acid and cyamelide produced by heating urea;
(C) aldehyde; and a
(D) a basic or acidic catalyst;
An additional aspect of the invention is use of the mixture cyanuric acid and cyamelide compounds, cyanuric acid and cyamelide salts of phosphorus and/or boron compounds and cyanuric and cyamelide-aldehyde resins as flame retardant compounds. The flame retardant use comprises contacting a more flammable organic material with the mixture of cyanuric acid and cyamelide and/or cyanuric acid and cyamelide salts of phosphorus and/or boron containing compounds and/or cyanuric acid and cyamelide-aldehyde resins thereof under conditions sufficient to lower the combustibility of the otherwise more flammable organic material, for example plastics, natural products or polyurethanes. Thus, a further aspect of the invention is a flame-retardant composition comprising a more flammable organic material incorporated therewith or applying on a flame retardant amount of a mixture of cyanuric acid and cyamelide and/or a mixture of cyanuric acid and cyamelide salts of a phosphorus and/or boron containing compound, and/or cyanuric acid and cyamelide-aldehyde resin, carbonization auxiliaries, metal compounds that accelerates the carbonization process, heat reflecting compounds and fillers.
The flame-retardant compounds of this invention are produced by heating urea (Component A) with urea or biuret to above the melting point of urea to about 160 degree C. at ambient pressure for 0.1-3 hrs. Upon heating above the melting point urea forms a very reactive compound isocyanic acid which will react with itself or other urea or other organic or inorganic nitrogen containing compounds especially amino compounds. In order to increase the flame retardant properties and carbonization properties of the mixture of cyanuric acid and cyamelide compounds, a carbonization auxiliary, such as, phosphorus acidic compounds, or organic phosphorus compounds that will react with an amino compound; boric acid, etc., is added to the melted cyanuric and cyamelide compounds mixed and/or reacted. Other carbonization auxiliaries may be mixed with the mixture of cyanuric acid and cyamelide compounds such as urea phosphate, melamine phosphate, magnesium phosphate, etc., to produce the flame retardant cyanuric acid and cyamelide composition. The mixture of cyanuric acid and cyamelide may be further reacted with an aldehyde in the presence of a neutral or basic or acidic catalyst by mixing and heating the mixture of cyanuric acid and cyamelide compounds with the aldehyde, usually in an aqueous medium, to just below the boiling point of the components at ambient or an elevated pressure thereby producing a cyanuric acid and cyamelide-aldehyde resin. Carbonization auxiliaries may be added to the mixture of cyanuric acid and cyamelide compounds or the cyanuric acid and cyamelide-aldehyde resin. The mixture of cyanuric acid and cyamelide compounds and cyanuric acid and cyamelide-aldehyde resins with or without carbonization auxiliaries and fillers may be reacted with or added to or applied on a more flammable organic material.
It is preferable to produce the mixture of cyanuric acid and cyamelide by utilizing urea which is heated sufficent to produce a mixture of cyanuric acid and cyamelide.
Urea is utilized as component A and may be in the form of a powder, crystals or a solid. Any suitable urea may be utilized that will condensate when heated to form a mixture of cyanuric acid and cyamelide. The mixture is utilized in the amount of 100 parts by weight when reacted with another compound.
Any suitable aldehyde may be reacted with the cyanuric acid and cyamelide compounds. Suitable aldehydes include, but not limited to, formaldehyde, paraformaldehyde, acetoaldehyde, butyraldehyde, chloral, and other alkyl aldehydes, furfural, benzyl aldehyde and other aromatic aldehydes. Aqueous formaldehyde is the preferred aldehyde. The aldehyde is utilized in the amount of 0 to 200 parts by weight. When it is utilized it is used in the amount of 25 to 100 parts by weight.
Any suitable carbonization auxiliaries may be utilized in this invention. Suitable carbonization auxiliaries are compounds that in the presence of fire assist the formation of a carbonization foam or char, such as, additives that produce acidic components in the pyrolysis mixture, such as phosphorus acids, boric acids or sulfuric acids. These acidic components are compounds such, for example, acids or salts, or their derivatives of sulfur, boron and phosphorus, such as, boron-phosphates, phosphates, and polyphosphates of ammonia, amines, polyamines, amino compounds, thioureas and alkyanolamines, but boric acid and its salts and their derivatives, organic phosphorus compounds and their salts, halogenated organic phosphorus compounds, their salts and their derivatives may also be used for this purpose. The carbonization auxiliaries and other flame retardant agents may be used in quantities of 0 to 300 parts by weight. The carbonization auxiliaries and other flame retardant agents are not a necessary component but when used is used in an amount of 5 to 300 part by weight.
The nitrogen containing salts of phosphorus acids are the preferred carbonization compounds, such as amino phosphate, amino salts of organic phosphorus compounds and amino condensation salt of inorganic and organic phosphorus compounds. The condensation salt of phosphorus compounds are produced by contacting a mixture of cyanuric acid and cyamelide with a phosphorus containing compound that will react with an amino compound, under conditions sufficient to prepare a cyanuric acid and cyamelide salts of a phosphorus containing compound. Suitable inorganic phosphorus compounds include, but not limited to, phosphoric acid, pyrophosphoric acid, triphosphoric acid, metaphosphoric acid, phosphorous acid, hydrophosphorous acid, phosphinic acid, phosphinous acid, phosphine oxide, phosphorus trihalides, phosphorus oxyhalides, phosphorus oxide, mono-metal hydrogen phosphates, ammonia dihydrogen phosphate, bromated phosphates, alkali metal dihydrogen phosphate and halogenated phosphate-phosphite and their halides and acids organic phosphorus compounds include, but not limited to, alkyl, cyclic, aryl and alkyl-aryl phosphorus compounds, such as, alkylchlorophosphines, alkyl phosphines, alkyl phosphites, dialkyl hydrogen phosphites, dialkyl alkyl phosphonates, trialkyl phosphites, organic acid phosphates, organic diphosphonate esters, aryl phosphites, aryl hydrogen phosphates, halogenated phosphonates esters and mixtures thereof. Cyanuric acid and cyamelide borates may be produced by contacting boric acid and a mixture of cyanuric acid and cyamelide compounds under conditions sufficient to prepare the mixture of cyanuric acid and cyamelide borates which may also be utilized as a flame-retardant compound. A mixture of cyanuric acid and cyamelide salt of boron-phosphates may be produced by contacting boron-phosphates and a mixture of cyanuric acid and cyamelide compounds under conditions sufficient to prepare cyanuric acid and cyamelide salts of boron-phosphate compounds which may also be utilized as a flame-retardant compound. The salt forming phosphorus containing compounds will react with the mixture of cyanuric and cyamelide compounds to form cyanuric acid and cyamelide salts of a phosphorus containing compound.
Any suitable metal-containing compound that will accelerate carbonization effect used in this invention increases the amount of carbonization residue after combustion, thereby enhancing the flame retardant effect and may be used in this invention. These compounds include, but not limited to, alkaline earth metal borates such as magnesium borate, calcium magnesium borate and the like, manganese borate, zinc borate, metal oxides of titanium oxide, tin oxide, nickel oxide, zinc oxide and the like, ferrocene, dimethylglyoxime copper, acetyl-acetonatocooper, hydroxyquinoline nickel and the like, zinc thiocarbamate compounds such as zinc dimethylthio-carbamate, zinc di-n-butyidithiocarbamate and the like, mercaptobenzothiazole zinc compounds such as mercaptobenzothiazole zinc and the like, salicyadehyde zinc compounds such as salicylaldehyde zinc and the like, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium magnesium hydroxide, zirconium hydroxide and the like and mixtures thereof. The most preferable compounds are selected from zinc oxide, zinc thiocarbamates, the mercaptobenzothiazole zinc compounds the salicyaldehyde zinc compounds, zinc borate and the alkaline earth metal borates. The are utilized in the amount of 0 to 30 parts by weight.
Any suitable compound that will reflect heat compound such as titanium oxide may be used in this invention and used in the amount of 0 to 30 part by weight.
Any suitable filler may be used in this invention. The fillers that may be utilized in the flame retardant mixture are usually insoluble in the reaction mixtures. They may be inorganic substances, such as, alkali metal silicates, alkaline earth metal silicates, metal silicates, silica, metals, oxides, carbonates, sulphates, phosphates, borates, glass beads or hollow glass beads. Hydrated aluminum oxide is preferred. They may be organic substances, such as, amino compounds, such as urea, melamine, dicyandiamide, and other amino derivatives or their formaldehyde resins, amino phosphates, amino salts of organic phosphates, phenolaldehyde resin powder, powdered coke, graphite, graphite compounds and mixtures thereof. The organic halide flame retardant compounds may also be added as fillers. The filler may be used in the amount of 0 to 300 percentage based on the weight of the partially hydrolyzed amino condensation compound.
Any suitable basic or acidic catalyst may be used in the reaction of amino condensation compounds with aldehydes. Suitable basic compounds include but not limited to, compounds containing alkali metal, alkaline earth metal and ammonia radicals and mixture thereof. Suitable acidic compounds include, but not limited to,halogen acids, acidic phosphorus containing compounds, acidic compounds containing sulfur, sulphonic acid, halides, carboxylic acids, polycarboxylic acids, nitric acids and mixtures thereof. In some reactions basic or acidic catalytic are not necessary. A catalytic amount is utilized.
Any suitable organic material which is more flammable than the mixture of cyanuric acid and cyamelide, its salts and cyanuric acid and cyamelide-aldehyde resins may be used in this invention. Any suitable plastic resin composition or mixtures thereof and any suitable natural organic material maybe used in this invention and mixtures thereof. These materials may be in the form of a solid, cellular suspension, emulsion or solution. Suitable plastic resin include, but not limited to, vinyl dienes, vinyl-diene copolymers, polyesters, polyester resins, phenoplasts, aminoplasts, polyepoxy resins, polyurethanes, furans, polyamides, polyimides, polycarbonates, homopolymers of such olefins as ethylene, propylene, and butylene; block copolymers, consisting of optional combination of these olefins; polymers of vinyl compounds such as vinyl chloride, acrylonitrile, methyl acrylates, vinyl acetates and styrene; copolymers of the foregoing olefins with vinyl monomers, copolymers and terpolymers of the foregoing olefins, with diene compounds; polyesters such as polyethylene terephthalate, polyester resins; polyamides such as nylon; polycarbonates, polyoxymethylene, silicones, polyethers, thioplasts, polytetrafluoroethylene, polysulfones, vinyidienes, poly(vinyl acetate), aliphatic allyl compounds, polyacrylonitrile, aliphatic dienes, polybutadiene, butadiene-acrylonitrile, butadiene-styrene copolymers, aromatic vinyl compounds, heterocyclic vinyl compounds, cyclic unsaturated compounds, urethane-epoxy resins, polyimides, urethane silicates, cellulose nitrate rayon, regenerated cellulose film cellulose acetate, cellulose esters, cellulose ethers, cyanoethyl cellulose, chlorinated rubber and mixtures thereof.
Suitable natural products include but not limited to wood, cellulose, lignin-cellulose, paper, cotton, wool, linen, dammars, copols, other natural resins, rosins, lignin, natural rubber, natural proteins, e.g., soya bean protein, silk, glues, gelatin, etc.; modified cellulose and mixtures thereof. Natural organic material and plastics may be mixed together. The mixture of cyanuric acid and cyamelide compounds, and/or its salts, and/or cyanuric acid and cyamelide-aldehyde resins or cyanuric acid, and/or cyamelide compositions maybe utilized in the amount of 3-200 percent, percentage based on the weight of the more flammable organic material.
In general, the mixture of cyanuric acid and cyamelide are compounds which are produced by heating urea with urea or biuret. The heated urea first form isocyanic acid and/or cyanic acid which polymerizes with itself and when heated sufficient form a mixture of cyanuric acid and cyamelide.
Any amount of the mixture of cyanuric acid and cyamelide and/or its salts, and may include carbonization auxiliaries, metal carbonization accelerators, heat reflectors and fillers suitable for this invention, may be utilized. Preferably, flame retardant amounts of the mixture of cyanuric acid and cyamelide compounds and/or its salts and/or the cyanuric acid and cyamelide-aldehyde resins and/ or the cyanuric acid and cyamelide composition are from 3 percent by weight to about 200 percent by weight of the more flammable organic materials such as polyester resins, polyepoxy resins, polyurethane components, acrylic and acrylate resins, polyacrylonitrile, polystyrene, etc.
One method to measure this flame retardant capability is an oxygen index test. By selecting the various combinations of the mixture of cyanuric acid and cyamelide compositions to incorporate into a more flammable organic material the average limiting oxygen index (LOI) can be raised 10 to 30 percent or more when compared to otherwise comparable samples without the flame retardant mixture of cyanuric acid and cyamelide composition. For example the LOI of three flexible polyurethane foams with the mixture of cyanuric acid and cyamelide composition were raised more than 30 percent to a LOI of 31.7, 30.3 and 30.7.
When the mixture of cyanuric acid and cyamelide composition was incorporated into rigid polyurethane foam and tested with a propane torch with a 2xe2x80x3 flame held against the foam for one minute, the flame did not spread, the foam melted and/or a char was formed. The flame went out when the torch was removed.
Various mixtures of cyanuric acid and cyamelide compositions were incorporated into liquid resins then cured into a solid in the form of a xe2x85x9xe2x80x3xc3x972xe2x80x3xc3x976xe2x80x3 sample, for example, flexible polyepoxy resins, rigid polyepoxy resins, polyester laminating and flexible resin, polystyrene resin, polymethyl methyl acrylate resin, polyvinyl acetate resin, polyurethane, polyisoprene, polyethylene, acrylonitrile, etc, then tested with a propane torch having a 2xe2x80x3 flame, and held against the sample for one minute, the flame did not spread, and went out when the flame was removed. Various mixture of cyanuric acid and cyamelide compounds or compositions was add to aqueous emulsions and organic solutions of the above plastics then dried to form a test sample, then tested as above. The meltable plastics above was melted and the various mixture of cyanuric acid and cyamelide compounds or compositions were incorporated into the melted plastics then molded into a test sample and tested as above. The said above material were tested without the mixture of cyanuric acid and cyamelide composition and all burned.
The flexible flame retardant polyurethane foams were tested and passed the Calif. TB 133 test which utilizes a 100 gms of wood in the form of a crib being burned on top of the flexible foam. If more than 60 gms of the foam bums away it fails this test.
Various natural products such as wood shingles, paper, cotton cloth, and cardboard were coated with various cyanuric acid and cyamelide compositions in an aqueous emulsion containing 20% by weight of the powdered mixture of cyanuric acid and cyamelide condensation composition with or without adhesives, then after the product had dried, they were tested by applying a 2xe2x80x3 flame from a propane torch against the products, and the flame did not spread whereas the non coated products caught on fire and burned.